Further evidence for the presence of a ventral component of globus pallidus in the olfactory tubercle was obtained by comparing the characteristic staining patterns of acetycholinesterase (AChE), succinate dehydrogenase (SDH), and by measurements of the size of neuron cell bodies. In AChE stained sections, some neurons of the dorsal globus pallidus are stained heavily for this enzyme. A similar pattern is found in olfactory tubercle. This supportive evidence is matched by the consistency of the display of neurons stained heavily for the enzyme SDH in both ventral and dorsal pallidum. Preliminary size class analysis of neuron cell bodies reveals that large size classes are heavily represented in ventral pallidum. Other observations suggest that the large size classes of cells tend to be AChE-positive. These data provide further support for the hypothesis of a pallidal component in the tubercle.